- Migration of plants, animals and other species outside their native ecological niches represents a danger overhyped by some ecologists, contends a scientist who once decried such threats.
- Mark Davis of Macalester College asserts that we should worry about invasive species only when they create a direct threat to health or economic well-being. Extinctions from invaders remain the exception. Nonnative species do not usually drive out plants and animals when they reach a new place.
- Isolated places, such as islands, represent the one setting in which the nonnatives can frequently cause the endemic population to disappear.
- Davis maintains that we simply must get used to the reality that species do not stay put.
Plant ecologist Mark A. Davis will not participate in this year’s “Buckthorn Roundups” around his St. Paul, Minn., neighborhood. Davis will not tag along as these intrepid crusaders set out to eradicate the common and glossy buckthorn, two ornamental shrubs imported in the 19th century from Europe. The nonnatives have now taken over some Midwestern forests, prairies and wetlands. That is why eco-minded volunteers eagerly wrench young weeds from the soil, hack away at thick stems and douse remaining stumps with herbicides. Their hope: a return of Minnesota to its primeval state.
At one time, Davis, too, could see the logic in eradicating these “invaders.” He even advocated planting only Minnesota native plants on the Macalester College campus where he teaches. That changed in 1994, when he read an essay by journalist Michael Pollan in the New York Times Magazine that made his blood boil. He bristled at Pollan’s statement that turning the “ecological clock to 1492 is a fool’s errand, futile and pointless to boot.”
This article was originally published with the title A Friend to Aliens.